The Evil Queen
by xnemos
Summary: Emma returns to work at Boston Police Department to find out that she is being sent undercover to reveal the secrets of Dr. Regina Mills. Though all signs point to Regina being the murderer, things aren't always what they seem. SerialKiller!AU.


**Disclaimer: I do not own Once Upon a Time nor do I own any of the characters.**

 **A/N:** Hey guys! I haven't written in quite some time, but I couldn't shake this idea off so… Huzzah for writers block being gone after four long years? I hope you enjoy reading it, if not… Well, I enjoyed writing it! Have fun on this journey, and yes I already have this entire thing planned out...but as we all know, sometimes characters have a mind of their own. Oh, also. I should let you know that outside of TV shows and movies I have no knowledge on the Police stuff or Medical stuff so let's just call this my own world rules for now, ok? As for typos or weird sounding phrases, they're all mine. I have no beta reader. - **xnemos**

* * *

They say that your first time pulling the trigger and ending someone's life stays with you. What they don't tell you is that ending someone's life, even though it's because your life and other that you've sworn to protect lives were in danger, will haunt you every waking moment. They don't tell you how it changes you as a person. That it changes how you feel, how you act...how you think.

She takes another swing at the punching bag, her chest rising and falling. _You think you're going to make it through this?_ She hears. His voice brings chills to her body as she punches harder and begins breathing heavier. _You think you can actually save him? Save yourself?_ His voice echoes and she punches faster.

Hearing an alarm pulled her out of her thoughts, and she leaned against the punching bag. Tears were stinging her eyes, and she chalked it up to it just being swear. She struggled to get her breathing under control as she snatched her gloves off, reaching for her phone.

 _5:45am._ She let out a puff of air in release, grateful that she was going to have something else today to preoccupy her time. It was her first day back on the job.

With one last punch, not as hard as the other due to her no longer having her gloves on, she turned to go to her bedroom. Picking up some clothes, she went to the bathroom to take a shower and get ready for the day.

As Emma stepped in to the shower, she let the scalding water pour over her. She released a shaky breath, running her hand through her hair and resisted the urge to punch the shower wall. She had finally gotten cleared to go back to work and now her nightmares decided to make a comeback.

The nightmares that kept her up at night. The nightmares that were the reason she's been up since 2am, going for a run and then hitting the punching bag. She needed this to be over and down with. She needed them to go away.

Emma stepped out of the shower and dried off looking in the mirror. She hoped she didn't look as bad as she felt as she was going to have to convince her captain that she was ready for duty. She leaned against the counter, took a few calming breaths and closed her eyes. _I'm okay. I can do this._ She thought to herself as she pushed off the sink and dried up.

She was dressed in blue jeans with brown boots and wearing a white T-shirt with her trademark red leather jacket over it. _Red as the blood that was shed thanks to her_ she thought bitterly. Shaking her head, she looked at the time. _6:45am._ Fifteen minutes to get to work before she was deemed late. _Or probably a no-show if Captain had her way._

Grabbing her phone and making sure her door was locked - twice - she left and was grateful that the station was only a five minute drive away. Getting in her yellow Volkswagon beetle, she sent off a silent prayer to whoever was listening that she could have a normal day before driving off and making her way to the station.

* * *

 _Of course nothing can be normal,_ Emma thought bitterly, giving an awkward smile that was more of a grimace. People came up to hug her and welcome back, people who she didn't even know the name of.

The moment that Emma arrived at the 379th Precinct she was met by a round of applause, a cake that said Welcome Back!, and people coming to her to tell her how she's such a hero, such a _savior._ Her only saving grace was Detective David Nolan, and she let out a sigh of relief when she had finally caught his attention.

The moment he reached her, Emma looked at him with a glare and he shrugged, putting his hands up to signal innocence. "Did you do this, Nolan?" she hissed at him before shooting a fake smile to someone who was approaching her.

A flash of guilt crossed his face, something that Emma hadn't missed, and he shook his head. "I can assure you, Emma, that I would never do something like this." He said as he dropped his arms, looking over Emma's shoulder.

Emma followed his gaze and was met by a familiar face. Looking back at David she poked his finger at his chest. "Did your _girlfriend_ do this?" She asked, trying to keep as calm as possible. David had the decency to look embarrassed and shrugged once again. "She was your old roommate? She wanted to do something nice for you?"

Emma let out a groan and rolled her eyes, looking back at the woman. She started making her way over to her, moving with a sense of purpose, when their eyes connected. "Emma!" she said in a warm tone, excusing herself from the people she was talking to.

Holding up a hand to stop her from hugging her, Emma looked at her with a look of frustration. "Really, Mary-Margaret?" she asked, unable to keep the annoyed tone out of her voice. Mary-Margaret looked at her in confusion and just ask she started to speak she was cut off…

...by the Captain. The Captain let out a whistle and clapped her hands together. "Alright, that's enough. Back to work people." she said and looked over to Emma. "Detective Swan, welcome back." She said tersely. Emma mumbled a thanks and moved to go to her desk when she was stopped. "A word, please." she heard her say and she turned around to walk into her office.

Following the captain, Emma turned back to shoot Mary-Margaret who still had a confused look on her face a glare.

"Please, close the door and have a seat." she heard her boss say. Emma did as directed and sat in the chair at the position of attention. "Captain Blue." she said with a slight nod of her head. Blue smiled slightly at her, something behind that smile, and then looked down at the paperwork on her desk.

There was silence for a few minutes, the only thing that could be heard was the humming coming from Blue. Emma started to fidget in her chair, though she desperately tried her best not to. "I see you've been cleared by the psychiatrist." she started, looking at Emma to say anything before she continued.

Once Blue was sure that Emma wasn't going to say anything, she placed the file back on the table. Emma stared at Blue, having a bad feeling as to where the conversation was going to lead. "We all know how much you love being in the field…" she started off, tapping her pen on the table. "But I should have you know that I'm not sure you're completely ready for that yet, having been out for three months."

Despite her best efforts, Emma flinched as she heard Blue say out loud how long she's been gone. _Three months. Three months of self-loathing. Three months of getting back in shape. Three months running away…_

She snapped out of those thoughts as Blue continued. "...on desk duty for two weeks. At the end of those two weeks I will see how you're doing and determine whether or not you're ready for the field. Understand?" Having toned out on part of the conversation, Emma looked at Blue in alarm.

"What do you mean two weeks? Captain I've been gone _three months!_ " Emma exclaimed, trying to keep her voice down as much as possible. The way the Captain looked at her gave her said that she had no other choice. "And another two won't hurt, _Detective_ Swan. So I suggest you get back to work and catch up on what you've missed in these three months." she said, successfully ending the conversation.

Emma got up, blood boiling and turned away to leave the office before she said something she'd regret. Once she was out of the office, and far away enough that she was sure Blue couldn't hear her, she growled in frustration and looked around for something to hit.

Before she could find anything, David was by her side and cast a sideways look at Emma. "Desk duty?" he asked. She clenched her teeth. "Two weeks." she said. David gave her a sympathetic smile and offered her a cup of coffee. She raised her eyebrow and he shrugged. "Peace offering?" he said, his voice light. Emma sighed and nodded, taking the cup and a gulp of the hot liquid.

"At least that gives you time to catch up on this case that we've been working on." He says, trying to find the silver lining. Emma nodded, mind elsewhere. "I suppose you're right" she replied.

David looked at Emma and resisted the urge to sigh. There was something about her that changed, and he knew that going through what she did could and would change anyone, but it didn't make it any better. "Emma...if you ever want to talk about-" he started, but before he could finish he was cut off. "I don't." she said, her tone harsh as her body tensed up.

Before he could say anything else, she walked off and he hung his head, hurt but not surprised by the rejection.

Making her way over to Ruby and Leroy who were talking to Belle, the Medical Examiner, she caught the tail end of their conversation. "-with no heart, I wonder how many more will show up."

Emma stared at the board, looking at the pictures of multiple victims as well as a woman who was labeled as the main suspect. "The Evil Queen?" she asks before she's able to stop herself as she furrows her eyebrows in confusion.

At the sound of Emma's voice, everyone turned to look at her and she shifted uncomfortably, not wanting their attention on her. She sent them a small wave and gave them an awkward smile. "Hey guys…"

Ruby was the first of her daze and ran up to hug Emma, though stopping right before she reached her as she wasn't sure how'd she react to it. "Emma!" she said, excitement and warmth in her tone. "I'm _so_ glad you're back." Emma smiled at her. Glad to be to catch me up on the case?" she asked, trying to take the focus off of her.

Ruby turned to the board and nodded. "Yeah, totally. Of course. Recently there's been bodies discovered that have been dumped through the city. Normally we would think that the cases we unrelated but each victim shared the same thing, they were missing their heart. Uniqure, right?"

"After digging through some things, we've found out that most, if not all of the victims have known or in some way come in contact with Dr. Regina Mills, Head of Cardio-thoracic Surgery at Mass Gen. This shows us that she has the skill set to remove these hearts, she also claims that while at the time of death of the past five bodies we've found, she's been watching her son so that means…"

"No solid alibi." Emma says, the pieces connecting. Ruby smiles at Emma and nods. "exactly, no solid alibi. The total body count as of now is fifteen-" Emma winced at that number, wondering how someone who promised to save lives came to kill so many "-and we're trying to prevent that number from rising. We have reason to believe that she is either selling the hearts on the black market...or keeping them as trophies." Ruby finished, a small grimace on her face.

Emma nodded slowly, still looking at the board. More specific, at the picture of Regina Mills. "So where does the name "Evil Queen" come in?" she asked, not understanding how any of the information she'd received would dub this woman as the evil queen.

Leroy snicked at the question and smirked at Emma, a look that made her want to punch him in the face. "That's what all the interns and residents she works with call her." he said, though his tone signaled that he wasn't done talking. "But when I met her, she seemed more like the Evil Bitch" he finished.

Emma and Belle rolled their eyes at Leroy's antics as Ruby punched him in the arm. "Leroy!" she said disapprovingly which made him grumble. He began muttering something about how _it's true_ and _why did they even care what he called a murderous bitch._

Emma bit her lip, wheels turning in her head before looking at the three and David who was now making his way over to the group. "This all seems pretty cut and dry…. Why haven't we arrested her?"

They all looked at each other sheepishly and David scratched his head. "Well, we did…" he began, looking at the others for help. When he realized they'd be no good he sighed and continued. "But we could only hold her 36 hours without charging her with something.. And she has a hell of a Lawyer." he grumbled. The group all nodded in agreement, remembering when the time they brought her in.

Before anyone could say another word, Blue came out of the office and scanned the room. "Swan, my office." she stated before turning around and walking back into her office.

Suddenly the entire room was quiet and she could feel everyone's eyes on her. She took a deep sigh and wondered what she was in trouble for this time as she made the walk to the office. _Why does this feel like a death march…_ She thinks to herself as she notices people shooting sympathetic looks in her direction.

Once she reaches the office, she stands awkwardly in the doorway. "Once again, Detective. Please close the door and have a seat." Emma did as she was told, and if it was possible was more nervous than she had been earlier.

"Detective Swan, I know I said you will be on desk duty for two weeks but a...situation just came up and we need you to go undercover." Emma's eyes widened at this, and a smirk began to appear on Blue's face. "That is, if you feel ready for that after last time."

Emma narrowed her eyes and nodded, not trusting her voice at the moment, or herself to say something appropriate. When she realized that Emma wasn't going to speak or give her the reaction she wanted the smirk fell off her face and she continued.

"Very well. As you are aware of by now, we brought Regina Mills in and therefore she knows the faces of all the people who are working this case. Well, all but one. You. Your goal is to get close to her and get her to trust you enough to let you in. Whatever information you receive will be of help." Emma nodded as she focused on what Blue was saying.

While thinking about the last time she went undercover, the nerves started getting to her. She took a deep breath and focused on the task at hand. Yes, she was going to go undercover again but it was either that or stay at a desk job.

And there was something about this case that was pulling her in.

"Yes ma'am, understood. Is there anything else I should know?" she asked, looking at Blue. "You start in three days. In that time I want you to know all the information we have on Regina Mills front and back. I want you to know Regina Mills better than _Regina Mills_ knows Regina Mills. For the next three days you are going to eat, sleep and drink information about Regina Mills and there will be nothing more important than that, do I make myself clear?"

Emma felt her lip twitch, and she couldn't help herself from what she was going to say next. "That's _Doctor_ Regina Mills…" she said, looking the captain in her eyes. "...ma'am." she added, not wanting to further annoy the brunette.

Emma turned around to walk out but Blue spoke before she could get away. "Detective Swan?" She said evenly. Emma turned around to face her, waiting to see what she had to say. "Don't screw this one up."

There was a flash of guilt in Emma's eyes, but as quickly as it appeared it disappeared. "I won't ma'am." she responded quietly before opening the door and stepping out of the office.


End file.
